The Torah in Parashat Korah (Bamidbar 18:18) commands that a person’s firstborn ox, sheep or goat is considered sacred, and must not be redeemed. Whereas a firstborn child is redeemed from a Kohen, a firstborn kosher animal may not be redeemed, and must be given to a Kohen. A firstborn kosher animal differs in this regard from a firstborn donkey, which may be redeemed, as the Torah discusses elsewhere. As the Sefer Ha’hinuch writes in a different context, the Torah commands us to give firstborn animals to a Kohen in order to heighten our awareness of the fact that everything we have has been given to us by Hashem. By giving the first animal to G-d, we are reminded that we do not actually own anything, as everything has been mercifully granted to us by G-d as a gift. If we would redeem the firstborn animal, then its sacred status would have less of an impact upon us, and so the Torah forbade redeeming the firstborn animal, requiring us to instead give it to a Kohen. After the Bechor (firstborn) is given to a Kohen, the Kohen must offer it as a sacrifice. However, once the animal develops a Mum (disqualifying blemish), the Kohen is permitted to eat or sell the animal. A blemished Bechor may be sold even to a gentile. Nowadays, when the Bechor cannot be offered as a sacrifice, the Kohen may sell it immediately, even before it develops a Mum. However, even nowadays, he cannot eat the Bechor unless it has become blemished. This Misva applies in the Land of Israel, and even nowadays. It is binding upon Kohanim, Leviyim and Yisraelim. If one attempts to redeem his Bechor by transferring its sanctity onto money, the redemption is ineffective, but he has nevertheless transgressed this Biblical prohibition. Even though he has not altered the animal’s status, the attempt to effect a Pidyon (redemption) itself violates this command. The person is not liable to Malkut, however, because the Pidyon is done verbally, without performing an action, and Malkut are administered only if one transgresses a Biblical command through an action.